1. Field
The following description relates to a method for preventing oxidation of a silver nanowire conductive film and to a silver nanowire conductive film coated with an oxidation protection layer.
The present application is based on the result of global frontier business/veteran researcher supporting business (Project name: Superhigh Speed Charge Collection Nanomaterial Design and Synthesis Technology Development: 2011-0031606/Three-dimensional Nanostructure Flexible Optical Electrode Development for Organic-Inorganic Hybrid Flexible Thin Film Solar Cell Implementation: 2011-0017210)(Managing department name: National Research Foundation of Korea (NRF))(Ministry name: Ministry of Education and Science Technology (MEST)) and the result of knowledge economy technological innovation business (new renewable energy technology development business)(Project name: Non-electrolyte Super Optical Wavelength Absorption Thin Film Solar Cell Development: 2010-T100100460)(Ministry name: Ministry of Knowledge Economy)(Research management professional organization: Korea Institute of Energy Technology Evaluation and Planning (KETEP)).
2. Discussion of Related Art
A considerable amount of research has been conducted in the recent years to develop flexible and transparent conductive films. In particular, research on transparent conductive films that include silver as the conductive element has been quite active. Silver has the highest conductivity among elements of the periodic table in form of nanoparticles. However, the conductivity of silver nanoparticles decreases over time due to oxidation.
As shown in FIG. 1, sheet resistance of a silver nanowire increases rapidly as time elapses. The conductivity of a silver nanowire is lowered due to the increase in sheet resistance.
Silver in a bulk state has excellent corrosion resistance and thus is not well oxidized. However, in case of nanoparticle-sized silver, due to a substantial increase in surface area, the reactivity of the nanoparticle-sized silver increases and the nanoparticle-sized silver particles are thus oxidized, causing the conductivity of silver to decrease. Thus, when a flexible transparent conductive film is fabricated using silver nanowires, the performance of the silver nanowire conductive film may deteriorate over time due to oxidation. However, existing researches focus on a method of fabricating a flexible transparent conductive film using silver nanowires without addressing the performance degradation caused by oxidation of the silver nanowires.
In actuality, performance characteristics, such as flexibility, light transmittance, and conductivity, are important to fabricate and commercialize the use of a flexible transparent conductive film that includes silver nanowires. Further, in the event that the flexible transparent conductive film is not used in fabricating a display device as a replacement for ITO, in many applications, the reliability of conductivity of the film is more important than the transmittance or transparency to utilize nanoparticles of silver. Thus, it is desirable to determine a method of reliably maintaining the conductivity of the silver nanoparticles for a long time.